Shudder To Think
by began-to-climb
Summary: There's this boy in his arms, in his life, and Derek cannot picture anything before him. Future!Derek/Stiles, angst smut


**Title: **Shudder to Think**  
Rating:** NC-17  
**Summary:** There's this boy in his arms, in his life, and Derek cannot picture anything before him.  
**Disclaimer:** I do not own any of the characters depicted or mentioned in this story.

He hasn't had anything in seven years.

In the years since the fire, possessions were the clothes on his back, the keys in his pocket and a dilapidated structure of ash that he couldn't look at. Romantic entanglements, those few and far between, once burned twice shy, rarely lasted longer than a month, just in time to catch scent and take off once again. The roof over his head and the lights were only monetary.

He hasn't had anything in seven years, but there's this boy in his arms, in his life, whole heart handed over and cradled in the sockets of his palms, and Derek cannot picture anything before him, cannot imagine anything after him.

Their bodies aligned as if made for each other in mind, the younger man's lip caught between his teeth, Derek watches Stiles shiver inexorably as Derek's cigarette fingers trail across his collarbone and wrap loosely around the column of his throat, his own hands tracing the swirls of the triskelion on Derek's back. Derek tips Stiles' head, nails scraping along his jaw, and rains a shower of kisses over his skin from collarbone to ear, tongue flattening over the bobbing Adam's apple, laving to the brink of beleaguered.

With the steady rhythm of Derek's hips rocking into the pocket of Stiles' body endeavoring pinched gasps and moans that ring memoranda in Derek's ears, the two stare at one another, panting headily on each other's lips. In these little moments, connected with Stiles on such a nakedly human level, Derek is grateful for the fierce possession he has over the wolf, grateful for the control that came with the role of alpha over three years ago, which permits him to reflect back every emotion that Stiles sends out to him. To protect and satisfy Stiles in every way he can, knows how, now that the wolf's consistent demand that he be claimed, be put in his place and taught what to do as both a mate and part of the pack is staunched.

Derek swivels his hips as he pulls out and pushes back in, a low growl rumbling out as Stiles, never one to go out with a whimper, pitches forth the filthiest moan. His whole body trembles under Stiles' touch, convulsions of pleasure encasing him thoroughly and uncontrollably. He feels like he's seconds away from tripping over a live wire, cauterized by the heat encasing his cock and the intensity thrumming from Stiles' fingers that move frantically over every inch of Derek, needing to close any sliver of space left to separate them.

He isn't surprised by this, by how starved Stiles acts, not after all the losses, after the incident last year that could be repeated in a matter of hours. He should've warned Stiles, Derek thinks, should've warned him that this thing works both ways (maybe then Stiles wouldn't be clutching Derek with everything in him, terror underlined in his murmured words and touches that Derek won't come back this time like Isaac didn't come back, like Lydia, like Scott). Their lips meld together once more, breathing for each other; a rope of saliva strings between them when Derek moves away, sitting back on his heels, hands caressing Stiles' thighs, effectively yanking him forward, skin slapping noisily.

Stiles braces his hands against the headboard behind him, teeth impaling his bottom lip. "Derek," he gasps, "I'm gonna…"

The warning passes on tacitly. He works his hips against Derek's, meeting every move, fucking himself on Derek's cock as efficiently as Derek drills into him. Because this is how it is, how they are, two of Newton's pendulums, the cause and effect of each other. It's how they fit, a key to a lock, and Derek thinks no one's ever fit him quite like Stiles. Stiles who has only ever seen light while his whole world was clouded by darkness. Stiles, still so young and reckless, who thinks only of others and never for himself. Stiles, quiet and subtle in his fierceness, the fiercest of them all, of anyone Derek's ever fought beside. Stiles who he deucedly loves.

"Fuck," Stiles groans, the word rushing out between his teeth, his jaw clenching around the hum of Derek's name that follows and, Christ, Derek needs that hum, needs it open and loose and just his. He lays over Stiles, knees finding purchase, and thrusts harder, deeper, faster, slaked only when Stiles arches into his push as his heart lurches vociferously in his chest, when that melodic, telling, gleeful chuckle flusters from his throat. "Fuck, fuck, fuck," he chants, breaths coming in staccato huffs with each of Derek's thrusts, absolutely maddening in the sensation on Derek's neck.

And then he enjoins, "Switch," and it all shifts.

When Derek pulls out Stiles' hand immediately goes for his cock, vein protruding in the most beautiful hue, and Derek likewise can't ignore the coiling need. He places his hand over Stiles' as he gets into position behind him, fingers slipping between the crevices of Stiles' own to stroke, the flush rising and rising, the glossing head a rubicund scarlet. They're pressed back to chest, Stiles' head falling onto Derek's right shoulder, the younger man rubbing his ass against Derek's cock, the way it slides and slips in the crease, the way it catches in certain spots firing shocks through their bodies.

He won't ever not need this: Stiles' laugh, Stiles' cock heavy in his hand, Stiles' heart stuttering when they touch, Stiles rebutting every decision, Stiles, Stiles, Stiles. This unforeseen twist is the only thing he gives credence to chuckle at, to hide his face in his partner's neck and smirk against the skin, and if he were to Stiles would cackle right alongside him, as incredulous by the undertaking of his life as Derek.

It's still unnerving, even to this day, after two years that this is what it feels like to be mated, to have someone as a constant, to need their breath just so he can breathe.

Derek licks into Stiles' mouth in the same heartbeat that his cock fits into its familiar pocket, the puckered hole accommodating, and it's a strange strain, but not so unfamiliar for every millimeter of Stiles' body is familiar and explored and loved and marked and there isn't a surface of each other they haven't tasted or touched. There is nothing terra incognito about them and the sentiment impels the beat further.

Stiles' left knee is hooked in the crook of the older man's elbow, the hand attached to that elbow splayed over his speckled chest, holding him in place, and he chooses then to slither his hand along their bodies. It skates over Derek's abdomen, prompting an involuntary shudder, and reaches around to grasp Derek's ass, pantomiming for deeper. His fingers go white, marking crescents undoubtedly, as Derek obliges, going so hard and fast that the only sound from the younger man is a drawn mewl until he comes over his fingers, a cry tethered to the end of a sob.

He's unsteady in the aftermath as is custom, head dropping like a weight onto the pillow, bottom lip between his teeth in anticipation while Derek goes on. But it won't be long now, always so close behind each other, Newton's pendulums forever. And Derek can feel it now, the heat, the spring at the base of his spine unspooling at a rapid descent, almost to the last gate of resistance, right there, right there.

He feels his cock swelling before he can catch it, whining "Stiles" in that warning of tides to come. Stiles falls onto his back in hurried succession, Derek moving between his legs, grasp gentle on his hips, shifting them so close together. Stiles drags his fingernails over the line of hair trailing down as Derek aligns their hips and with a hitched breath, the smell of his cum comingling naturally with Stiles confounding his senses, all goes still as if a string has been pulled taunt and they're both waiting to be handed the scissors.

Derek covers Stiles, careful not to throttle their precarious position, and brackets Stiles' head with his forearms, knees pillaring the thighs that cradle his hips. He kisses whatever expanse of skin he can reach. He whispers things Stiles won't remember he said. He leans into Stiles' hand in his hair, the hand that is grasping his hair so tight, the dark mop that he's let grow out for this reason alone, to give Stiles something to anchor to as his body splits open in another way entirely. Anything to distract him, anything to ease him; anything, everything.

Because he's never felt it, never been on the receiving end of his knot. He only know his side of things, how it's like trying to push over a dame made out of concrete, how he's Alice growing much too big for the house. That desire for the comfort of fullness is there, though replaced.

"You're gonna kill me, babe," Stiles quips.

There's a smile, brave visage adjusting to its place (though his grip doesn't lessen), and Derek releases a breath, nuzzling Stiles' nose. "Shut up," he replies in replica of an old self, of a more brutal, broken self that had to hide everything, that couldn't be vulnerable like he can now.

Stiles grins, closing his eyes while Derek kisses his lips, kissing every pained twist that creases his face. "Derek?" The older man hums in response. "Come back."

"I'll try," he says though it disheartens him, wrecks him.

"I don't want 'try,'" and Stiles' face is so absurdly phlegmatic for what he asks. "I need 'will.'"

But that's the frailty of humans, of beings. Derek briefly presses his nose into Stiles' cheek, inhaling him, memorizing him. He'll be leaving in only a few hours and he knows Stiles will stew, will hug the pillow under his head or stay in the bathroom until Derek's gone, his juvenile comeuppance for agreeing to aid in a territory dispute. Stiles will refuse a goodbye, as he always has, as he continues to do, because goodbyes are forever and he isn't ready to watch another coffin descend.

So to his words Derek says, "I'll come back for you," and then he falls into a kiss in the same way they both fall into false hope they're desperately trying to masquerade. As always they fall together.

Derek hopes he does return. He knows he will. He'll fight teeth and nails for it if he has to. Because he finally has something—someone—to come back for.

And nothing can change his heart's focus.


End file.
